Embodiments of the present disclosure generally relate to methods and devices for controlling a timing of multi-point pacing therapy based on pacing latency.
Clinical studies related to cardiac pacing have shown that a desired (e.g., optimal) atrio-ventricular pacing delay (e.g., AV delay or PV delay) and/or a desired (e.g., optimal) interventricular pacing delay (e.g., VV delay) can improve cardiac performance. However, achieving a desired delay depends on a variety of factors that may vary over time. Thus, what is “desired” may vary over time. Selection of a desired AV/PV pacing delay and/or VV pacing delay may occur at implantation and sometimes, may occur during a follow-up consultation. Once the AV/PV and VV pacing delays are set, the benefits may not be long lasting due to changes in various factors related to device and/or cardiac function. Various systems and methods are provided for, inter alia, allowing a pacemaker or IMD to determine and/or adjust AV/PV/VV pacing delays so as to help maintain the pacing delays at desired values. In particular, techniques were set forth for exploiting various interventricular conduction delays to determine AV/PV/VV pacing delays.
Other techniques have been set forth for determining AV/PV delays based on inter-atrial conduction delays and interventricular conduction delays. In particular, see U.S. Pat. No. 7,248,925, to Bruhns et al., entitled “System and Method for Determining Optimal Atrioventricular Delay based on Intrinsic Conduction Delays,” which is fully incorporated by reference herein.
Certain types of patients (e.g., patients experiencing heart failure), who receive unipolar and bipolar cardiac resynchronization therapy (CRT) devices, may experience challenges such as phrenic nerve stimulation, high pacing thresholds and nonresponse to CRT therapy. Managing these challenges can result in longer implant times and surgical revisions. Today, new types of CRT devices are being utilized with a lead located proximate to the left ventricle (LV) that includes multiple electrodes distributed along the LV lead. For example, a quadripolar LV lead has been introduced that includes four distributed LV electrodes, such as to provide multi-point pacing (MPP) in a single coronary sinus branch.
While the availability of an MPP LV lead provides further improvement to CRT clinical outcomes, a desire remains to improve further timing and automatic programming guidance.